Short answer: a non-polar liquid like gasoline is more likely to bead up (form droplets) on a waxy polar surface, rather than spread out. Reasoning and context

• A waxy surface is largely non-polar and presents weak adhesive interactions with non-polar liquids. The cohesive forces within gasoline (a mixture of non-polar hydrocarbons) tend to dominate, causing the liquid to minimize contact with the surface by forming droplets. This is the classic beading behavior driven by surface tension and low surface energy of the surface. [general surface-tension concepts apply, including beading on low-energy surfaces]
• In contrast, polar liquids (like water) spread or bead depending on surface energy and interactions, but non-polar liquids typically bead on non-polar or weakly polar surfaces due to poor wettability. On a waxy surface, gasoline’s non-polar nature aligns with the surface’s low polarity, leading to limited adhesion and droplet formation. [surface-tension and wettability principles]

Key concepts to understand

• Wettability is governed by the balance of adhesive forces between the liquid and the surface versus cohesive forces within the liquid. When adhesive forces are weak relative to cohesive forces, beading occurs. [surface chemistry fundamentals]
• Contact angle is a practical measure: high contact angles (approaching or exceeding 90 degrees) indicate poor wetting and droplet beading; low contact angles indicate good wetting and spreading. Gasoline on a waxy (low-energy) surface would typically have a higher contact angle, promoting beading. [wetting theory]

Implications and practical notes

• If the goal is to improve spreading of gasoline on a waxy surface (e.g., for cleaning or uniform coating), one would typically need to introduce stronger adhesive interactions or surface treatments that increase surface energy or polarity to promote wetting.
• For surfaces that are waxy or nonpolar, non-polar liquids tend to bead, while polar liquids may bead less or interact differently depending on surface composition and cleanliness. These tendencies are broadly observed across typical beading and wettability discussions in surface science.

If you’d like, I can tailor this explanation to a specific surface (e.g., a waxed car finish, a polyethylene surface, or a technical waxy coating) and include a simple schematic of contact angle behavior.